The present invention relates generally to disposable absorbent articles. Specifically, the present invention relates to disposable absorbent articles designed for improved leakage protection.
Disposable absorbent articles such as disposable diapers, training pants, protective underwear, and the like are known. A typical disposable absorbent article frequently makes use of an absorbent core located between a top sheet and a back sheet. The top sheet is commonly formed of a material which is pervious to body fluids, e.g., urine, to allow the transfer of such fluids into the core. The back sheet is commonly formed of a liquid impervious material to provide a barrier wall so that fluid absorbed by the article cannot leak from the back sheet. The absorbent core is used to absorb the body exudates of the user wearing the article. Typically, fluff e.g., wood pulp or other cellulosic fiber, is used as the material of choice for the absorbent core.
In order to improve the absorbability of the absorbent core, highly absorptive polymers, sometimes referred to as “superabsorbent polymers” or “SAP” (which may be in the form of particles or fibers), are included with the fluff. However, the absorption rates of the absorbent core are not typically high enough to absorb a large quantity of liquids at a single time when such quantities are released onto the upper surfaces of the top sheet and the core. As a result, the liquid, at least partially, flows laterally onto the upper surface of the sheet and often leaks out along the side edges of the article. Such leakage occurs when the quantity of body fluid released is large.
In order to prevent such leakage, leakage-protecting baffles or cuffs are typically provided on the side edges of articles such as diapers. These cuffs contain a longitudinal elastic band. The cuffs secure the side edges of the diaper to the wearer's body, thereby preventing released body exudates from escaping from the diaper. However, in such designs, body exudates usually accumulate near the cuffs. Accordingly, there is always a possibility of the accumulated liquid leaking out from gaps formed between the cuffs and the body of the person wearing the diaper, for example when the wearer moves. Moreover, there is also a risk of liquid leaking out due to damage to the cuff
U.S. Pat. No. 4,579,556 discloses a disposable diaper in which the opposite side edges of the absorbent core are covered with part of an impervious back sheet, thereby achieving a certain degree of leakage protection. However, there is a possibility of leakage of body exudates when the side edges are subjected to body pressures.
U.S. Pat. No. 4,892,528 discloses a disposable diaper in which two sheets, resistant to the passage of water, are disposed adjacent to and partially outward from two side surfaces of the absorbent core. The two sheets along with the back sheet are used to make leakage-protecting baffles, which extend above the top surface of the absorbent core. In this invention, there is a risk of released body exudate leaking out once such extended baffles twist due to body movement.
U.S. Pat. No. 5,167,653 discloses a disposable garment provided with a plurality of flaps extending along laterally opposite sides of the garment and normally biased by the elastic shrinking potential to turn upwards. The design of this invention makes the garment complicated and difficult to wear because of multiple flaps containing elastic members.
In light of the above described disadvantages, what is required is a disposable absorbent article that effectively prevents leakage. Additionally, the disposable absorbent article should prevent liquids from leaking irrespective of body movements or the posture of the person wearing the article.